| Test Name | Prolactin |
|---|---|
| Used For | Aiding in evaluation of pituitary tumours, amenorrhea, galactorrhea, infertility, and hypogonadism.Monitoring therapy of prolactin-producing tumours. |
| Method | ImmunoenzymaticAssay |
| Aliases | PRL (Prolactin) |
| Specimen Type | Serum (Yellow) |
| Volume of sample | >0.25ml |
| Refrigerated stability | 7 days |
| Interfering substances | Haemolysis |
| Clinical Information | Prolactin is secreted by the anterior pituitary gland and controlled by the hypothalamus. It is structurally related to growth hormone (GH), but has few, if any, of the physiological effects of GH. The major chemical controlling prolactin secretion is dopamine, which inhibits prolactin secretion from the pituitary. The only definitively known physiological function of prolactin is the stimulation of milk production. In normal individuals, the prolactin level rises in response to physiologic stimuli such as sleep, exercise, nipple stimulation, sexual intercourse, hypoglycaemia, postpartum period, and also is elevated in the newborn infant. Pathologic causes of hyperprolactinaemia include prolactin-secreting pituitary adenoma (prolactinoma, which is 5 times more frequent in females than males), functional and organic disease of the hypothalamus, primary hypothyroidism, section compression of the pituitary stalk, chest wall lesions, renal failure, and ectopic tumours. Hyperprolactinemia often results in loss of libido; galactorrhea, oligomenorrhea or amenorrhea, and infertility in premenopausal females; and loss of libido, impotence, infertility, and hypogonadism in males. Postmenopausal and premenopausal women, as well as men, can also suffer from decreased muscle mass and osteoporosis. The latter can sometimes be dramatic in a small subgroup of women who develop severe and acute onset postpartum osteoporosis that remits with cessation of breastfeeding and medical suppression of hyperprolactinaemia. |
| Interpretation | Disease states associated with elevated serum prolactin levels include renal failure, untreated hypothyroidism, large nonprolactin-secreting pituitary tumours that have led to pituitary stalk compression, and prolactin-secreting pituitary micro- and macroadenomas. Mild to moderately increased levels of serum prolactin are not a reliable guide for determining whether a prolactin-producing pituitary adenoma is present, whereas very high levels are usually associated with a prolactin-secreting tumour. After initiation of medical therapy of prolactinomas, prolactin levels should decrease substantially in most patients; in 60% to 80% of patients, normal levels should be reached. Failure to suppress prolactin levels may indicate tumours resistant to the usual central-acting dopamine agonist therapies; however, a subset of patients will show tumour shrinkage despite persistent hyperprolactinemia. Patient who show neither a decrease in prolactin levels nor tumour shrinkage might require additional therapeutic measures. Resurgent prolactin levels in patients on long-term therapy indicate, most often, noncompliance with dopaminergic therapy, but can occasionally be an indication of recurrence. |
| Turnaround | 1h |
| Retention Time | 7 days |
| References | Mayo Clinic Laboratories |
| Lab Tests On Line |
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